Large-Scale Moisture Exchange in the Tropical Indian and Pacific Oceans in El Nino/Southern Oscillation Years

Moisture exchange is studied via composites for seven dry years and five wet years over India (with negative and positive summer precipitation anomalies of 10% above normal), during which a warm or a cold El Nino/Southern Oscillation phase developed in the succeeding fall and winter months. Analysis is based on the 1950-1999 monthly mean NCEP/NCAR reanalysis data. Specific features of the formation of the tropospheric integral moisture content anomalies, a major heat source, in the tropical Indian and Pacific oceans in ENSO years are shown. The zonal and meridional moisture transport and the moisture flux convergence are shown to play an important role in this process. Also, the important role of large-scale moisture exchange in a general chain of the tropical climate system anomalies in ENSO years is demonstrated.